Because of the lack of a lopinavir/ritonavir (LPV/r) pediatric formulation, 54 HIV-infected children were given generic LPV/r adult tablets. Of 54 children, 21 took cut pills to get the appropriate dose. The median (interquartile range) LPV trough serum concentration (C trough) was 6.7 (5.0-9.9) mg/L. All the children had C trough >1.0 mg/L and 96% had values >4.0 mg/L. LPV/r adult tablets can be used in children when it is necessary.